Fuel delivery

SAZERAC

MEMBER
FORD F-150

I live in rural Alaska and cannot get good information about my truck. My 1990 Ford F150 4whd auto w/od 5.8l engine, 101,286 miles will not start. It began to run rough over time, became difficult to start. Alternator was bad, changed alternator Changed the rail fuel filter. Then the engine would not start. When I turn the key on the fuel pump begins to run and will not shut off. I switched tanks and the other pump runs continuously. Our town mechanic loaned me his fuel pressure tester and I attached it to the schrader valve and turned the engine over. It read 45psi. I checked the spark plugs and there is fire across the tips. In desperation I sent the ECM to an outfit in Grand Prarie, Texas. They said they rebuilt the ECM, charged me $200.00 and sent it back. I reinstalled the ECM yesterday, same problem. Fuel pump runs continuously, will not start. I am out of ideas. Your help will greatly appreciated. Best Regards Regg

2 Replies

MERLIN2021

MECHANIC
17,250 POSTS

Contiuosly running pum. After key is off? Replace the relay! Then maybe a good tune-up.

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Monday, July 9th, 2007 AT 7:31 AM

SAZERAC

MEMBER
2 POSTS

I cannot start my 1990 Ford F150 5.8L 4whd auto 102,218 miles. The question that I asked your mechanics last week was, "The fuel pump runs continously when I turn the key on and the engine will not start, what is the cause? 2carpro mechanic answered my question with, "If the key is off and the fuel pump runs continously change the fuel pump relay". The opposite is the situation with my truck. The fuel pump runs continously with the key on and the vehicle will not start. Thank you for your help. Regg